Polymerization of alkylenimines



United States Patent N0 Drawing. Filed Aug. 30, 1962, Ser. No. 220,547 Claims. (Cl. 260-4.)

This invention concerns a new process for the polymerization of alkylenimines. More specifically, the invention concerns the use of small quantities of poly-halogenated alkanes, in conjunction with trace amounts of certain metals or metal compounds, to initiate mass or solution polymerization of alkylenimines.

Polyalkylenimines are used extensively for a wide variety of purposes. For example, they are employed as impregnating agents to impart desirable characteristics to textiles and paper, as adhesive bonding agents and as flocculating agents. The presently known methods for preparing these polymers employ a solvent system, generally water, to yield a solution of the polymer product. Complete removal of the solvent is extremely difficult and in the process of solvent removal permanent and undesirable changes in the polymer characteristics often result. Although the polyalkylenimine is generally employed in the form of an aqueous solution, it would frequently be more advantageous and economical to employ the pure undiluted polymer.

It has now been discovered, in accordance with the present invention, that polyhalogenated alkanes may be advantageously employed, in conjunction with trace amounts of certain metals or metal compounds, to initiate the mass or solution polymerization of alkylenimines. Although the polymerization of bulk monomer is a unique and desirable feature, the method of the invention may also be employed with a solvent system such as water, water-soluble alcohols or mixtures thereof.

The polyhalogenated alkane employed in the method where X is fluorine, chlorine, bromine or a combination thereof and n=1 or 2.

A quantity of polyhaloalkane suflicient to initiate the polymerization process, from about 1 to 5 weight percent based on the alkylenimine, is used. A concentration below one percent is undesirable since the polymerization rate becomes prohibitively slow and the final prod' uct viscosity, i.e., molecular weight, is objectionably low. At concentrations above about 5 weight percent, insoluble polymer gels tend to form.

The metal or metal compound adjuvant polymerization initiator is employed in trace amounts and is selected from elemental or ionic forms of metals in the Mendeleev Periodic Table Groups VIII and IB, i.e., iron, cobalt, nickel, ruthenium, rhodium, palladium, zosmium, iridium, platinum and copper, silver and gold. From about 5 to 500 parts per million (hereafter ppm.) metal based on the monomer used is preferred although the upper limit is not critical since the effectiveness of the metal is apparently due to that amount which is dissolved by the monomer and any excess is merely present as a residual impurity. There is no appreciable difierence apparent in results obtained when equal weights of the metal are employed in elemental and in ionic form.

3,200,088 Patented Aug. 10, 1965 The temperature maintained during the reaction influences the rate of polymerization and the final product molecular weight. The operable temperature range is from about 0 C. to the boiling point of the bulk monomer or monomer solution employed. Increasing the temperature accelerates the reaction and a temperature range of from about 25 to C. is preferred. Maximum viscosity results when a temperature of from about 40 to 60 C. is utilized. Normally the reaction is continued until polymerization is essentially complete. The length of time necessary to achieve this result will vary from about 1 to 10 days depending upon the concentrations of metal and polyhaloalkane employed as well as the temperature maintained.

The viscosity of the polymer, which is considered as a measure of molecular weight, is influenced by the same factors which effect the reaction rate. The viscosity increases as the amount of metal employed is increased with maximum viscosity resulting when approximately 50 p.p.m. of metal, monomer basis, is used. Similarly, the viscosity of the final product increases to a maximum value when the amount of polyhaloalkane initiator is increased to about 4 weight percent, monomer basis. As noted previously the viscosity of the final product is influenced by the reaction temperature with a maximum value reached when a temperature of about 50 C, is maintained. The viscosity of the final product does not appear to be influenced by the presence of a solvent in the polymerization system.

The alkylenimine monomer employed is selected from the group consisting of ethylenimine (hereinafter EI), propylenimine, 1,2-butylenimine, 2,3-butylenimine, isobutylenimine, trimethylenimine, and hexamethylenimine.

The following examples describe completely representative specific embodiments of the present invention. These examples are not to be interpreted as limiting the invention other than as defined in the claims.

EXAMPLE 1 of the monomer was essentially completed at the end ofa ten day period. This completion of reaction was shown by the absence of weight loss after vacuum drying the product overnight at 50 C. The copper was employed by adding sufiicient metal powder to E1 to provide a saturated solution. The BI solution of copper was analyzed to establish the meta-l concentration and subsequently diluted with pure E1 to the stated concentration.

Table I Exp. No G. of El Cu G. 0014 Viscosity (p-pn) An additional experiment was conducted in which 0.10 g. of dichlorobromornethane was employed in place of carbon tetrachloride, with 4.16 g. of EI and 70 ppm. Cu. The viscosity of the polymer product so obtained was 2. 12 cp.

The data in the foregoing experiments demonstrate the increase in polymer viscosity with increasing Cu content (up to a maximum here of 28 ppm. Cu) and increasing polyhaloalkane content.

EXAMPLE 2 This experiment was conducted to determine the effect of employing copper metal as compared with copper ion in the polymerizationor EI. at 25 C. and the reaction was essentially complete after three days at which time the viscosity measurements were made. The mixing and agitation procedures of Example 1 were followed. The concentrations and viscosities are tabulated below in'Table II. In this example the copper metal and copper salts were added directly to the E1 to be polymerized.

Table 11 Exp. No G. of E1 G. On CuCl2.2H2O G. Viscosity powder (G. Cu) C01 (cp.)

1 No polymerization.

In the above runs no polymerization occurred unless both polyhaloalkane and copper (elemental or ionic) were present.

EXAMPLE 3 Table III Exp. G. EI G. Cu G. G. Percent Viscosity No. 0014 polymer conversion 7 (cp.)

Although some polymerization occurs in the absence of the metal at elevated temperatures (Exp. No. 11) the result serves to emphasize the importance of the metal in order to obtain a higher percent yield of polymer and a higher viscosity, i.e. molecular weight, polymer product.

EXAMPLE 4 A series of experiments, according to the general pro- The'runs were conducted.

4 mer was employed in aqueous solution; The following table, Table IV, is a compilation of data from these tests which were run at 50 C. and 75 C. Polymerization was essentially complete after 24 hours. Copper metal and copper and iron'salts were employed as indicated. In each case 10g. of H 0 was used.

Table II [8.32 g. of E1 and 10 g. of water were used in each run] Exp. G. G. metal Temp, Viscosity No. 001 0. (e.p.)

0 50 0 0.003 o 50 0.08 0.003 Ou 50 4.12 0.159 0.003 On- 50 5.10 0.318 0.003 Cu 50 9.2 0. 477 0.003 Cu 50 5 25.0 0.159 CuCl-0.003 g. Cu 50 7. 78 0.159 omen-0.002 g. 011 50 6.62 0.159 Foch-+0002 g. Fe 50 2.01 0.159 FeCl;-0.001 'g. Fe 50 2. 35 0 75 0 0.003 Cu 75 0.016 0.003 Cu 75 3. 37 0. 048 0.003 Cu. 75 3.17 0.08 0 003 Cu-- 75 3. 43 0. 143 0 003 Cu.. 75 4.10 0.318 0.003 Cu 75 4. 24 0.318 (Incl-0.003 g.'Cu 75 4. 23 0.318 FeCl30.001g; Fe 75 3. 49

1 Controls.

2 No polymer.

3 Gel.

V ment that increasing polyhaloalkane content increases the cedure of Example 2, was conducted in which the mono .75

molecular weight and that thiseffect ismore pronounced at 50 C. than at F C. Both elemental copper and copperjsalts are shown to be more effective than iron salts in production of a higher molecular weight product; Any other Group VIII or IB metals as such or in' simple ionic form can be substituted with effective results.

We claim: 7 1. A'method for preparing v,p'olyalkylenimines which comprises mixing together at a temperature of 0 to 75C.: 1

(A) analkylenimine selected from the group consisting of ethylenimine, propylenimine,1,2-butylenimine, 2,3-butylenimine. ,isobutylenimine, trimethylenimine and hexamethylenimine; V (B) from about 1 to 5 weight percent, based on alkylenimine employed, of a polyhalogenated alkane selected fromthe group consisting of chloroform and a compound having the formula where X represents a member of the group consisting of fiuorine,'chlorine, bromine and mixtures thereof and n isan integer from 1 to 2 inclusive; and V (C) a metalliespecies ofthe group consisting of elemental and ionic forms of metals ofPeriodic Table Groups VIII and IB, said species being'p'resent at a concentration of at least about 5 ppm. metal based on the alkylenimine employed, for a time suflicient to eiiect substantial polymerization "of said alkylenimine. a p 7 2., The method of'claim'1 wherein the-alkylenimine is ethylenimine. j V

. 3. The method of claim 1' wherein the metallic species is copper. 7

4. 'The method of claim 1 wherein the alkylenimine is ethylenimine; the polyhalogenated alkane is carbon tetrachloride and, the metallic species is copper.

5. The method of claim 1 wherein said alkylenimine is 5 6 employed as a solute in a solvent selected from the group OTHER REFERENCES consisting of water, water-soluble alcohols and mixtures Salomon; il des Travaux chi i d p thereof. Bas, vol. 68, 1949, pp. 903-914.

Jones et al: Journal Organic Chemistry, vol. 9, pp. 125- References Cited by the Examiner 5 149 1944 v FOREIGN PATENTS MURRAY TILLMAN, Primary Examiner.

461,354 2/37 Great Britain. IRVING MARCUS, Examiner. 

1. A METHOD FOR PREPARING POLYALKYLENIMINES WHICH COMPRISES MIXING TOGETHER OAT A TEMPERATURE OF 0* TO 75*C.: (A) AN ALKYLENIMINE SELECTED FROM THE GROUP CONSISTING OF ETHYLENIMINE, PROPYLENIMINE, 1,2-BUTYLENIMINE, 2,3-BUTYLENIMINE, ISOBUTYLENIMINE, TRIMETHYLENIMINE AND HEXAMETHYLENIMINE; (B) FROM ABOUT 1 TO 5 WEIGHT PERCENT, BASED ON ALKYLENIMINE EMPLOYED, OF A POLYHALOGENATED ALKANE SELECTED FROM THE GROUP CONSISTING OF CHLOROFORM AND A COMPOUND HAVING THE FORMULA 